Viewing archive of Saturday, 11 October 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 Oct 11 1231 UTC

SIDC Forecast

Solar flares

C-class flares expected, (probability >=50%)

Geomagnetism

Active conditions expected (A>=20 or K=4)

Solar protons

Quiet

	10cm flux	Ap
11 Oct 2025	122	017
12 Oct 2025	126	012
13 Oct 2025	128	006

Solar Active Regions and flaring

Solar flaring activity was low over the past 24 hours, with six C1 flares identified. The most flaring solar region was SIDC sunspot group 639 (NOAA Active Region [AR] 4246, Beta magnetic configuration) with four C1 flares. SIDC Sunspot Group 621 (NOAA AR 4248, Beta-Gamma magnetic configuration) and SIDC Sunspot Group 664 (NOAA Active Region 4245, Beta magnetic configuration) produced one C1 flare each. More C-class flaring is expected in the next 24 hours, mostly from SIDC sunspot groups 621 and 639.

Coronal mass ejections

No Earth-directed Coronal Mass Ejections (CME) were observed in the last 24 hours.

Solar wind

The Solar Wind (SW) conditions are affected by a glancing blow from SIDC Coronal Mass Ejection (CME) 578 that arrived on the early hours of 11 Oct. The arrival caused the SW speed to increase from 340 to 460 km/s, while the interplanetary magnetic field (B) reached 15 nT, and its North-South component (Bz) fluctuated between -9 and 10 nT. The effect of the glancing blow is expected to last for approximately a day.

Geomagnetism

The global geomagnetic conditions reached the minor storm level (NOAA Kp 5-) on 11 Oct between 06:00 and 09:00 UTC. This is the result of the arrival of a glancing blow from SIDC Coronal Mass Ejection (CME) 578 at the early hours of 11 Oct. The local conditions followed a similar pattern, although they only reached active levels at the time of the global minor storm. For the next 24 hours both the global and local conditions are expected to wane and reach up to active levels.

Proton flux levels

The greater than 10 MeV proton flux, as measured by the GOES-19 satellite, was at background levels over the past 24 hours and is likely to remain so in the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux as measured by GOES 19 was above the 1000 pfu alert threshold on 10 Oct between 12:00 and 21:20 UTC, with a peak value at 2300 pfu. In increased again above the alert threshold for a brief period on 11 Oct between 04:45 and 06:00 UTC. For the rest of the past 24 hours the flux was below but close to the alert threshold. In the next 24 hours it is expected to repeat a similar pattern. The 24-hour electron fluence was at moderate levels during the past 24 hours. It is expected to marginally drop and remain at moderate levels in the next 24 hours.

Today's estimated international sunspot number (ISN): 106, based on 08 stations.

Solar indices for 10 Oct 2025

Wolf number Catania	087
10cm solar flux	121
AK Chambon La Forêt	015
AK Wingst	010
Estimated Ap	011
Estimated international sunspot number	077 - Based on 22 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

All times in UTC

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